This invention relates to synthetic polymeric resin compositions useful for thermoplastic fabrication and, more particularly to thermoplastic blends of extrudable and moldable urethane polymers and ABS resins.
Thermally processable polyurethanes having high modulus and good thermal properties are known to be useful in the manufacture of auto parts such as distributor covers as well as covers and containers for electronic circuitry. See, for example, U.S. Pat. 4,822,827. Typically, such polyurethanes can be produced by the reaction of a polyisocyanate with a cycloalkane polyol having a molecular weight in the range from about 60 to about 400.
Unfortunately, such polyurethanes do not exhibit the impact strength required for many applications. To increase impact strength of such polyurethanes, it has been a practice to incorporate minor amounts of impact modifiers such as high rubber content ABS resins, methyl methacrylate/butadiene/styrene terpolymers, chlorinated polyethylenes, ethylene/vinyl acetate copolymers as well as certain multi-phase composite polymers into such polyurethanes. Such practices have met with only limited success with the resultant blends exhibiting only moderately improved impact strength and often reduced stiffness. In addition, the resultant blends often do not exhibit sufficient processability to be readily extruded and molded into desired shapes.
In view of these deficiencies of the conventional high modulus, thermally processable polyurethanes, it is highly desirable to provide an impact modified polyurethane composition which exhibits improved toughness and stiffness and good thermal processability.